The invention relates to a collecting device for collecting floating dusts in the atmosphere.
Among the fine particles floating in the atmosphere, those particles having a diameter less than 10 xcexcm are called suspended particle matter (SPM). Although these floating dusts contain sands, they are mainly composed of black smokes, unburned materials, sulfur compounds and the like (35% of these is generated from diesel engine cars in the Kanto District, Japan), and it is said that they are highly toxic. The dusts from the exhaust gas from the diesel engine car are specially called diesel exhaust particles (DEP). Also, the particles floating in the atmosphere having a particle smaller than 2.5 xcexcm are called micro-particulate matter (PM2.5), and have been extensively researched and studied. It is said that the exhaust gas from the diesel engine car is a likely source of the PM2.5.
In addition, as the particulate matters floating in the atmosphere, the yellow sands can be mentioned. The yellow sands are blown up by strong wind at inland desert of Chinese Continent and carried to Japan over the sea by the strong westerlies. Although particle diameters of the yellow sands differ depending on a location, the yellow sands in Chinese Continent near the desert have particle diameters in a range of 20 to 30 xcexcm, and the particles reaching Japan far from the desert have diameters in the order of 4 to 5 xcexcm.
Further, the particulate matters floating in the atmosphere include pollens. Recently, with increase in the number of people who suffered from a variety of pollinosis, information on the pollens floating in the atmosphere becomes important. The pollens of Japanese cedars and Japanese cypresses are said to be main causes of the pollinosis. The pollens of these plants have substantially a sphere shape with a diameter in the order of 30 to 50 xcexcm.
As a method for measuring the floating dusts described above, there has been a method wherein the atmosphere is sucked in and passed through a filter to collect the floating dusts on the filter. Then, a microscope is used to observe the dusts for determining shapes and the number of the particles. There has been also a method wherein the floating dusts in a certain volume of the atmosphere are collected on the filter in the above-stated method, and weights of the filter before and after the collection are measured to obtain the quantity of the particles. In addition, there has been a method wherein the floating dusts collected on the filter in the same manner as described above are processed, and the extracted chemical components contained in the floating dusts are identified by a gas chromatograph mass spectrometer, liquid chromatograph mass spectrometer or spectrum analyzer.
Also, to measure a particle size distribution of the floating dusts (SPM) and micro-particulate matters (PM2.5) in the atmosphere described above, a cascade-impactor type device has been practically used. The cascade-impactor type device utilizes an impacting process of suddenly changing a flow direction of a medium with the particles through colliding against a collecting plate, thereby separating the particles with a specific size from the medium. The cascade-impactor type device is structured such that a plurality of impactors, each having a 50% collecting efficiency at a specific particle diameter, is connected in series of multi-stage. A particle diameter of the dusts collected with the 50% efficiency at each stage represents an average particle diameter for each stage. Thus, the particle size distribution can be obtained from the quantity of the dusts collected from each stage.
Also, as a collecting method of the pollens floating in the atmosphere, a slide glass with an adhesive such as Vaseline coated on a surface has been used. The slide glass with the adhesive thereon is placed in the atmosphere, thereby allowing the pollens in the atmosphere to fall down thereon. The pollens adhered to the slide glass are observed by the microscope to thereby measure a shape, size, number, kind and the like.
Also, as a method for measuring a concentration of the floating dusts, there has been used a method wherein a certain volume of the atmosphere is sucked in and passed through a filter to trap the dusts therein. Then, weights of the filter before and after the collection are measured with an electronic balance or the like. The concentration of the floating dusts in the certain volume of the atmosphere can be determined from the weight difference.
Also, as a device for effectively collecting the floating dusts in the atmosphere, an electrostatic-type particle collector has been known. In the electrostatic-type device, the particles floating in the atmosphere are charged by ions generated from a discharge electrode. A dust-collecting electrode with a different potential relative to the discharge electrode is disposed to collect the charged particles. As the discharge electrode, a discharge electrode as shown in FIG. 14 has been often used in the electrostatic-type particle collector. The discharge electrode is formed of a number, i.e. several hundreds, of metal wires, and the wires are bundled with a brush tip at one end.
In the collecting method using the filter to analyze SPM and PM2.5 with the microscope or various chemical analyzing instruments, it is very difficult to extract the floating dust individually. Therefore, in the case of the microscopic observation, the floating dusts adhered to the filter are observed with the microscope as they are. In this case, the particle image may be blurred because of a background filter image. Also, in the case of conducting various chemical analyses, since the floating dusts are difficult to remove from the filter, it is difficult to do the analyses. For example, in the case of a fluorescent X-ray analyzer, it is difficult to irradiate the X-ray only on the particles.
Further, it is difficult to conduct the spectrum analysis, since the floating dusts are not separated each other on the filter and electromagnetic wave is difficult to focus on a single particle. Also, the gas chromatograph mass spectrometer or the like is difficult to apply as the floating dusts are hardly separated from the filter.
In the conventional method for measuring the concentration of the floating dusts, the filter is easy to absorb water, thereby causing an error in measuring the floating dusts due to the absorbed water. Also, in this method, it is necessary to weigh the filter twice. Therefore, it is difficult to measure a real time change in the concentration, and the work is also troublesome.
Moreover, in the case that a laser diffraction particle size analyzer is used to determine the particle size distribution, it is necessary to irradiate a laser beam to the floating dusts having a concentration within a specific range to obtain appropriate diffracted or scattered light. In order to provide the floating dusts in the concentration range suitable for the measurement, for example, a specific quantity of the floating dusts may be collected through suction of the atmosphere for a certain period of time. However, the concentration of the floating dusts in the atmosphere is not constant and varies even during the collecting operation. Thus, at the time point when the collecting is completed, the quantity of the floating dusts is totally different from an expected value, and it is difficult to obtain a sample at a desired concentration.
Also, it takes long time to collect the pollens on the surface of the slide glass, for example, 24 hours, in the conventional method for collecting the pollens floating in the atmosphere. Also, a collected quantity per a specific period of time is influenced by wind and the like, so the collected quantity does not represent the actual pollen quantity existing in the atmosphere.
Also, when the microscope is used to observe the collected pollens, it is relatively easy to identify the shape and kind of the pollens. However, the information does not represent the whole pollens floating in the atmosphere since the collected pollens are influenced by wind and the like. Further, it is necessary to measure the respective diameters of the pollens to obtain a particle size distribution of the pollens, resulting in a complicated work.
In the conventional measuring device based on the cascade impactor method for measuring the particle size distribution of the floating dusts, an upper limit of the measurement is theoretically in the order of 10 xcexcm. In addition, the number of the collecting plates determines a resolution of the measurement. Therefore, even though it is desired that the particle size distribution be measured at a high resolution, there is a limitation.
In the conventional electrostatic-type particle collector as described above, it takes long time to manufacture the discharge electrode since a large number of metal wires need to be bundled together. In addition, it is necessary to have a step of making one end thereof in a brush shape, resulting in a high cost. Further, in addition to the cost, it is difficult to make the shape and structure of the discharge electrode uniform, resulting in a large variation in efficiency of generating the ions and collecting the particles in the particle collector.
In view of the above defects, the present invention has been made and an object of the present invention is to provide a device for collecting the floating dusts in the atmosphere, wherein the collected particles can be easily observed by the microscope and individual particles can be easily extracted for various analysis techniques. Another object of the invention is to provide a method for easily measuring the particle size distribution of the floating dusts in a wide range including particle diameter larger than 10 xcexcm with a high resolution.
In addition, an object of the invention is to provide a method for clearly observing the floating dusts in the atmosphere by the microscope without influence of the background.
Also, another object of the invention is to provide a method for accurately measuring the quantity of the floating dusts in the atmosphere.
Further object of the invention is to provide a method for accurately identifying the chemical components contained in the floating dusts when analyzed by the gas chromatograph mass spectrometer and the spectrophotometer.
Further, an object of the invention is to provide a device for measuring a concentration of the dusts, wherein a real time change in concentration of the floating dusts in the atmosphere can be measured with a simple operation, and the collected floating dusts can be easily subjected to various measurements. Also, an object is to provide a collecting device for securely collecting the floating dusts in a specific concentration range.
Further, an object of the invention is to provide a collecting method wherein the yellow dusts in the atmosphere are effectively collected, and the collected dusts are easily subjected to the microscopic observation and various analyses. Another object of the invention is to provide a measuring method for measuring the particle size distribution and the concentration of the collected dusts at a high resolution.
In addition, an object of the invention is to provide a collecting device for securely collecting the pollens floating in the atmosphere without influence of the wind or the like. Another object of the invention is to provide a measuring device for easily and accurately measuring the particle size distribution of the pollens floating in the atmosphere as well as the shape, kind and number of the pollens floating in the atmosphere without influence of the wind or the like.
In the conventional electrostatic type particle collector, the discharge electrode is formed of a large number of metal wires, and one end of thereof is formed in a shape of the brush tip. An object of the invention is to provide an electrostatic type particle collector having a particle collecting efficiency equal to or better than that of the conventional device with a new type of electrode. The present invention can reduce a manufacturing cost and have good reproducibility, thereby improving the quality of the products.
The present invention is to provide a particle collector, wherein the dusts floating in the atmosphere can be collected effectively. The collected dusts can be easily preserved as they are. As a result, it is easy to observe the collected dusts with the microscope. In addition, the collected dusts can be individually extracted, thereby easily applying the various analyses including the laser diffraction-scattering type particle size distribution device.
Further objects and advantages of the invention will be apparent from the following description of the invention.
In order to attain the above objects, according to the present invention, a collecting device for collecting dusts floating in the atmosphere includes a collecting container; a pump for sucking the atmosphere into the collecting container; a discharge electrode disposed in the collecting container and generating single polarity ions to charge the dusts in the collecting container; and a dust-collecting electrode for collecting the charged dusts in the collecting container through a potential difference between the discharge electrode and the dust-collecting electrode. The dust-collecting electrode is structured such that a transparent coating made of a conductive material is applied to at least one surface thereof facing the discharge electrode.
According to the present invention, a method for measuring the dusts floating in the atmosphere is a method for determining a particle size distribution of the floating dusts collected by the above-described collecting device. After the dusts floating in the atmosphere are collected on the surface of the dust-collecting electrode, a laser beam is irradiated to the dust-collecting electrode. Accordingly, a spatial intensity distribution of the diffracted/scattered light from the dusts on the electrode is determined, thereby obtaining a particle size distribution of the dusts.
According to the present invention, the collecting device of the dusts floating in the atmosphere can attain the objects by charging the dusts floating in the atmosphere; and collecting the charged floating dusts on the dust-collecting electrode formed of a transparent plate, such as a glass plate and a plastic plate, with a conductive coating by using the potential difference between the discharge electrode and the dust-collecting electrode.
More specifically, in the collecting device of the dusts floating in the atmosphere according to the invention, the pump pulls the atmosphere into the collecting container. When the discharge electrode disposed in the collecting container generates the single polarity ions, the floating dusts contained in the atmosphere are charged. The charged dusts are attracted toward the dust-collecting electrode having the potential difference with respect to the discharge electrode in the collecting container. The dust-collecting electrode is structured such that a transparent conductive material is coated on at least the surface of the transparent plate, such as a glass plate and a transparent plastic plate, facing the discharge electrode. Thus, the dusts are accumulated on the flat surface of the transparent plate and can be subjected to the microscopic observation as they are, to thereby observe a clear particle image without any influence of the background image. Also, since it is possible to extract a single particle, the chemical analysis using various analyzing equipments, such as a fluorescent X-ray analyzer, can be easily carried out. Also, since the dust-collecting electrode is formed of the transparent plate with the transparent conductive coating, even if a large quantity of the charged dusts are accumulated, the constant potential is maintained by connecting the electrode to the ground. Thus, an effective collecting can be attained.
Also, according to the invention, the measuring method of the dusts takes advantage of the fact that the collected condition of the dusts by the above-mentioned collecting device satisfies the requirements for the laser diffraction-scattering method to conduct the particle size distribution measurement.
More specifically, it has been known that the laser diffraction-scattering method can measure a particle size distribution over a wide particle diameter range at a high resolution. In the particle size distribution measurement based on the laser diffraction-scattering method, the spatial intensity distribution of the diffracted/scattered light is obtained by irradiating the laser beam on the particles to calculate the particle size distribution of the particles. In the laser diffraction-scattering method, the particles to be measured need to be in a dispersed state and the diffracted/scattered light must have a sufficient intensity. The collecting device according to the present invention collects the floating dusts on the dust-collecting electrode in a dispersed state. Also, the dust-collecting electrode of the invention is formed of the transparent plate with the conductive coating to keep the potential constant, so that the floating dusts can be effectively collected. Thus, a quantity (concentration) of the floating dusts on the dust-collecting electrode can be controlled through setting a collecting time and the like.
Therefore, the dusts floating in the atmosphere can be collected on the dust-collecting electrode until a proper concentration is obtained. When the laser beam is irradiated directly to the dust-collecting electrode to which the floating dusts are adhered, the diffracted/scattered light has a sufficient intensity for calculating the particle size distribution. The particle size distribution of the floating dusts can be obtained at a high resolution over a wide particle range in the order of a sub-micron to 10 xcexcm.
According to the present invention, a measuring method of the dusts floating in the atmosphere includes steps of charging the dusts floating in the atmosphere with the single polarity ions generated by the discharge electrode; collecting the charged particles on a solid dust-collecting electrode having a continuous surface through a potential difference between the discharge electrode and the dust-collecting electrode; and observing the collected floating dusts by a microscope to measure the shape and/or number of the particles.
Also, a measuring method of the dusts floating in the atmosphere according to the invention includes steps of charging the dusts floating in the atmosphere by the single polarity ions generated by the discharge electrode; collecting the charged particles on the solid dust-collecting electrode having a continuous surface through the potential difference between the discharge electrode and the dust collecting electrode; and measuring weights of the dust-collecting electrode before and after the floating dusts are collected thereon to thereby obtain a quantity of the dusts from the weight difference.
Further, a measuring method of the dusts floating in the atmosphere according to the present invention includes steps of charging the dusts floating in the atmosphere by the single polarity ions generated by the discharge electrode; collecting the charged particles on the solid dust-collecting electrode having a continuous surface through the potential difference between the discharge electrode and the dust collecting electrode; and identifying chemical components contained in the collected dusts by using one selected from or a combination of a liquid chromatograph mass spectrometer, a gas chromatograph mass spectrometer, a high-frequency induction binding plasma mass spectrometer, a spectrophotometer and a fluorescence X-ray analyzer.
Instead of collecting the floating dusts in the atmosphere by a filter, the present invention achieves the objects by charging the dusts with the single polarity ions from the discharge electrode, and collecting the charged dusts on the dust collecting electrode having the continuous flat surface, for example, a metal plate or a glass plate coated with a conductive material.
More specifically, when the floating dusts in the atmosphere are charged and electrically collected on the dust-collecting electrode having the continuous flat surface, the floating dusts are accumulated on the flat surface of the dust-collecting electrode in a dispersed state. Therefore, when the microscope is used to observe the collected dusts, a clear image of the respective particles can be easily obtained without an influence of the background image to thereby determine accurate shapes and the number of the particles.
Also, the dust-collecting electrode formed of the glass plate or metal plate does not absorb water. Therefore, the quantity of the collected floating dusts can be easily and accurately measured by measuring the weights before and after the dust-collecting electrode collects the charged dusts in the atmosphere.
Further, the floating dusts are collected on the dust-collecting electrode in a dispersed state, as described above, by collecting the charged dusts on the dust-collecting electrode having the continuous flat surface. Therefore, it is easy to apply the electromagnetic wave on the individual particle, and also the collected dusts can be easily extracted. Thus, the chemical components contained in the dusts can be easily and accurately identified with a liquid chromatograph mass spectrometer, a gas chromatograph mass spectrometer, a high-frequency induction binding plasma mass spectrometer, a spectrophotometer and a fluorescence X-ray analyzer.
According to the invention, a device for measuring a concentration of the dusts floating in the atmosphere includes a collecting container; a pump for sucking the atmosphere into the collecting container; a discharge electrode disposed in the collecting container and generating the single polarity ions to charge the floating dusts; a dust-collecting electrode formed of a transparent member for collecting the charged dusts in the collecting container through a potential difference with respect to the discharge electrode; a light irradiation device for irradiating light on the dust-collecting electrode; and a detector for detecting a transmitted light intensity of the light passing through the dust-collecting electrode, so that a result is output as a concentration of the floating dusts.
According to the invention, a collecting device of the floating dusts in the atmosphere includes a collecting container; a pump for sucking the atmosphere into the collecting container; a discharge electrode disposed in the collecting container and generating the single polarity ions to charge the floating dusts in the container; a dust-collecting electrode formed of a transparent member and having a potential difference with respect to the discharge electrode so that the charged dusts in the collecting container are collected thereon; a light irradiating device for irradiating light on the dust-collecting electrode; a detector for detecting a transmitted light intensity of the light passing through the dust-collecting electrode; and a control device for stopping the pump at a time when an output of the detector reaches a pre-set value.
Here, the dust-collecting electrode has a transparent electrode coated on a surface of a transparent plate, such as a glass plate and a resin plate. Alternatively, the dust-collecting electrode may have a structure where a transparent liquid, such as water, is contained in a dish or container formed of a glass plate on which a transparent electrode is coated, so that the floating dusts are collected in the liquid.
The present invention attains the objects by sucking the atmosphere into the collecting container, charging the floating dusts in the container with the discharge electrode, and collecting the floating dusts on the dust-collecting electrode formed of the transparent member, so that the concentration information of the floating dusts collected on the dust-collecting electrode can be obtained from the intensity of the transmitted light through the dust-collecting electrode.
More specifically, when the single polarity ions are generated from the discharge electrode while sucking the atmosphere into the collecting container, the floating dusts in the collecting container are charged. Then, the dusts are drawn and sequentially collected on the dust-collecting electrode, and accumulated uniformly on the surface thereof. Then, the light is irradiated on the dust-collecting electrode formed of the transparent member and the intensity of the transmitted light is detected. The detected value corresponds to the quantity of the dusts collected on the dust-collecting electrode. The total amount of the atmosphere sucked in the collecting container can be obtained from a flow rate of the pump and time. Thus, the concentration change of the dusts in the atmosphere with time can be obtained substantially at real time from the total amount of the sucked air and the detected value of the transmitted light intensity.
Also, the floating dusts are collected on the dust-collecting electrode, and then the transmitted light intensity through the dust-collecting electrode is detected, thereby obtaining the concentration information of the floating dusts in real time. Therefore, by automatically stopping the pump at a time when a value reaches a preset concentration, the floating dusts within a desired concentration can be collected.
According to the invention, a collecting device for collecting the floating dusts in the atmosphere includes a collecting container; a pump for sucking the atmosphere in the collecting container; a discharge electrode disposed in the collecting container for generating single polarity ions to charge the dusts in the collecting container; and a dust-collecting electrode having a different potential with respect to the discharge electrode so that the charged dusts in the collecting container are drawn and collected on the dust-collecting electrode. The dust-collecting electrode includes a transparent member provided with a recessed portion on a surface thereof, and a transparent electrode film coated on at least a bottom surface of the recessed portion.
The present invention attains the objects by charging the floating dusts in the atmosphere, and by collecting the charged dusts on the dust-collecting electrode through the potential difference. The dust-collecting electrode is provided with the recessed portion on the surface of a transparent member, such as a glass plate or a transparent plastic plate. Also, the transparent electrode is coated on the bottom surface of the recessed portion.
More specifically, in the collecting device of the present invention, when the pump sucks the atmosphere into the collecting container and the discharge electrode disposed in the collecting container generates the single polarity ions, the floating dusts in the atmosphere are charged. The charged dusts are drawn toward and collected on the dust-collecting electrode having a different potential with respect to the discharge electrode. The dust-collecting electrode has the recessed portion on the surface of the transparent member and the transparent electrode film is coated on at least the bottom surface of the recessed portion. Accordingly, the charged dusts are collected on the transparent electrode film in the recessed portion.
Since the floating dusts are collected in the recessed portion, a lid can cover the recessed portion so that the collected dusts can be easily preserved in a state as they are on the transparent member. Also, since the electrode is formed of the transparent member, the floating dusts can be subjected to the microscopic observation. Further, since the floating dusts can be easily extracted, the floating dusts can be subjected to various analyses. Also, the laser diffraction-scattering type apparatus can determine the particle size distribution of the floating dusts.
When the particle size distribution of the floating dusts is measured by using the laser diffraction-scattering type apparatus, before the spatial intensity distribution of the diffracted/scattered light from the collected dusts is measured, the standard particles dispersed in a medium liquid are sealed in the recessed portion of the dust-collecting electrode and the apparatus can be calibrated. Therefore, it is possible to eliminate variations in the particle size distribution measurements due to a shape of the dust-collecting electrode.
According to the present invention, in an electrostatic type particle collecting device, the discharge electrode generates the single polarity ions to charge the particles floating in the atmosphere, and the charged particles are collected on the dust-collecting electrode having a potential difference with respect to the discharge electrode. The discharge electrode is formed of a metal wire loop.
The present invention has been attained in view of a complicated conventional discharge electrode wherein several hundreds of metal wires are bundled and one end thereof is formed in a brush shape. The present invention provides an improved discharge electrode to meet the objects.
More specifically, the discharge electrode has a structure wherein a metal wire is formed in a loop shape. It was confirmed that the discharge electrode according to the invention has a discharging efficiency same or higher than that of the conventional discharge electrode. The discharge electrode has the simple loop shape structure, resulting in the high reproducibility. Thus, constant quality can be maintained, and the production cost can be reduced.
According to the present invention, in a collecting method of yellow sands, a pump sucks the atmosphere into a container; a discharge electrode disposed in the container generates the single pole ions to charge the floating dusts including the yellow sands in the container; and the charged particles are collected on a dust-collecting electrode having a potential difference with respect to the discharge electrode.
In the collecting method of the yellow sands according to the invention, the atmosphere is sucked into the container provided with the discharge electrode and the dust-collecting electrode therein. The yellow sand particles are charged by the single polarity ions from the discharge electrode to collect on the surface of the dust-collecting electrode. Therefore, it is possible to easily extract the yellow sand particles individually, so that the extracted yellow sand particles can be subjected to various analyses, and the observation by the microscope can be carried out easily.
Further, according to the present invention, a measuring method of the yellow sand particles includes steps of irradiating a laser beam on the particles obtained by the above-described collecting method in a dispersed state, measuring a spatial intensity distribution of diffracted/scattered light from the particles; and determining a particle size distribution and a particle concentration of a particle diameter range containing the yellow sand particles, from the measured results.
In the measuring method of the yellow sand particles according to the invention, it is possible to measure the particle size distribution and the particle concentration of the yellow sand particles at a high resolution by obtaining the particle size distribution of the yellow sand particles collected on the dust-collecting electrode, as described above, with the laser diffraction-scattering type apparatus.
More specifically, in the laser diffraction-scattering type apparatus, the laser beam is irradiated on the particles in a dispersed state to obtain the spatial intensity distribution of the diffracted/scattered light. The particle size distribution of the particles is obtained through the operations based on the scattering theory of Mie and the diffraction theory of Fraunhofer, from the spatial intensity distribution of the diffracted/scattered light. This is because the light intensity distribution complies with the scattering theory of Mie and the diffraction theory of Fraunhofer. According to the laser diffraction-scattering type apparatus, the particle size distribution can be obtained at a high resolution over a wide range of particle diameters by adjusting a concentration of a medium for dispersing the particles at a proper range.
However, when the laser beam is irradiated directly to the yellow sand particles in the atmosphere to measure the diffracted/scattered light, it is impossible to obtain the sufficient diffracted/scattered light for obtaining the particle size distribution due to a low concentration of the yellow sand particles in the atmosphere.
Therefore, in the present invention, the atmosphere is sucked into the container, and the particles including the yellow sand particles are charged in the container to collect on the dust-collecting electrode. Then the collected particles are dispersed with a concentration range suitable for the laser diffraction-scattering type measurement. The laser beam is irradiated to obtain the spatial intensity distribution. Thus, it is possible to measure the particle size distribution of the particles in the atmosphere over a wide range of the particle diameters like the normal laser diffraction-scattering type measurements. A pretest can be done to determine a particle diameter range of the yellow sand particles at a measurement location in advance. In other words, it can be confirmed that particles found in advance to be in the range are mainly the yellow sand particles. Thus, when only the particle size distribution in the particular range is measured, the result represents a correct particle size distribution of the yellow sand particles floating in the atmosphere.
Also, the laser diffraction particle size analyzer may be calibrated with particles whose concentration is known beforehand. As the quantity of the atmosphere sucked in the container can be easily calculated from a flow rate of the pump and an operation time, the concentration of the yellow sand particles in the atmosphere can be obtained.
According to the present invention, a collecting device for collecting pollens in the atmosphere includes a collecting container; a pump for sucking the atmosphere into the collecting container; a discharge electrode disposed in the collecting container for generating the single pole ions to charge the pollens in the collecting container; and a dust-collecting electrode having a potential difference with respect to the discharge electrode for collecting the charged pollens in the collecting container thereon.
Also, a measuring apparatus of the pollens in the atmosphere includes the above-described collecting device; a dispersing device for holding the pollens on the dust-collecting electrode in a dispersed state; an optical irradiation system for irradiating a laser beam on the pollens in the dispersed state; an optical measurement system for measuring a spatial intensity distribution of diffracted/scattered light from the pollens; and an operation device for calculating the particle size distribution of the pollens trapped on the dust-collecting electrode from the measured values.
Further, in a measuring method of the pollens in the atmosphere, a microscope is used to observe the pollens collected by the above-stated collecting device to determine the number, shapes and kinds of the pollens.
In the present invention, it is possible to collect substantially a whole quantity of the pollens in the atmosphere sucked in the container through the pump in a short time by electrically collecting the pollens without having any influence of wind or the like. Also, it is possible to quickly determine a particle size distribution of the pollens in the atmosphere by using the collecting device and the laser diffraction-scattering type apparatus. Further, it is possible to accurately measure the kinds, shapes and number of the pollens floating in the atmosphere by using the collecting device.
More specifically, when the pump sucks the atmosphere into the collecting container and the discharge electrode disposed in the collecting container generates the single polarity ions, the pollens in the atmosphere are charged. The charged pollens are drawn toward the dust-collecting electrode having a potential difference with respect to the discharge electrode in the collecting container, and collected on the dust-collecting electrode. By collecting the charged pollens in the collecting container on the dust-collecting electrode, substantially the whole quantity of the pollens in the atmosphere sucked in the trapping container can be collected. The result can represent a quantity of the pollens per unit volume of the atmosphere sucked in the collecting container without having any influence by the wind or the like.
Also, the measuring apparatus of the pollens according to the present invention is a combination of the above-described collecting device and the laser diffraction particle size analyzer. Since substantially the whole quantity of the pollens in the atmosphere sucked in the collecting container can be collected, a particle size distribution of the pollens floating in the atmosphere can be accurately measured.
More specifically, in the laser diffraction-scattering type apparatus, the laser beam is irradiated on the pollens in a dispersed state to obtain the spatial intensity distribution of the diffracted/scattered light. The particle size distribution of the pollens is obtained through the operations based on the scattering theory of Mie and the diffraction theory of Fraunhofer, from the spatial intensity distribution of the diffracted/scattered light. This is because the light intensity distribution complies with the scattering theory of Mie and the diffraction theory of Fraunhofer. According to the laser diffraction-scattering type apparatus, the particle size distribution can be obtained at a high resolution over a wide range of particle diameters, including 30 to 50 xcexcm of the various pollens, by adjusting a concentration in a medium for dispersing the particles at a proper range.
However, when the laser beam is directly irradiated to the pollens naturally floating in the atmosphere, it is impossible to obtain the sufficient diffracted/scattered light for obtaining the particle size distribution due to a very low concentration.
According to the present invention, the collecting device electrically collects the pollens floating in the atmosphere. The collected pollens are dispersed in a concentration range suitable for the laser diffraction-scattering type measurement. The laser beam is irradiated on the pollens to measure the spatial intensity distribution. Thus, the particle size distribution of the respective pollens can be accurately measured at a high resolution over a wide range of particle diameters.
A dispersing device is formed of a combination of a dispersing tank for dispersing the collected pollens in a medium liquid, and an agitator or an ultrasonic vibrator. The laser beam is irradiated on the pollens dispersed in the medium liquid. The dust-collecting electrode in the collecting device is formed of a transparent member. A glass plate may be placed on the duct-collecting electrode for covering an upper surface thereof so that the pollens do not fall off. The laser beam may be irradiated directly to the pollens sandwiched between the dust-collecting electrode and the glass plate.
According to the present invention, a microscope is used to observe the pollens collected by the above-described collecting device to measure shapes, the number and kinds thereof. It is possible to collect samples representing all the pollens floating in the atmosphere and perform the observation without any influence of the wind and the like, so that the observation results represent information of all pollens in the atmosphere.
In this case, it is preferable that a transparent member is used as the dust-collecting electrode, so that the dust-collecting electrode with collected pollens thereon can be subjected to the microscopic observation as it is.